The invention relates to a magnetic-tape threading apparatus comprising a deck carrying a cylindrical drum system provided with at least one rotating magnetic head, on which deck a supporting member carrying at least two mutually spaced tape guides is guided for rectilinear movement towards and away from the drum system, movement of the supporting member towards the drum system causes a length of magentic tape to be led towards the drum system, after which movement, when the supporting member is in an end position, the magnetic tape is wrapped around a part of the circumference of the drum system by the tape guides. When the supporting member is in the end position, the tape guides are positioned relative to the drum system by at least one positioning element.
A magnetic-tape apparatus of this kind is disclosed in U.S. Pat. No. 3,512,694. In this known apparatus the tape guides which wrap the magnetic tape around the circumference of the drum system are resiliently connected to the supporting member by means of blade springs. In order to ensure a sufficiently accurate transport of the tape around the drum system, which is necessary in such an apparatus because of the very small width of the tracks recorded on the magnetic tape, the drum system should be positioned accurately on the deck. The deck further carries positioning elements which position the tape guides accurately in the end position of the supporting member after the length of magnetic tape has been wrapped around the circumference of the drum system and after flexure of the blade springs. For a correct positioning of the drum system and the two tape guides relative to one another both the drum system and the positioning elements should be mounted accurately on the deck and, in addition, the deck must have a high rigidity and dimensional stability. Despite this accurate mounting of the drum system and the positioning elements on the deck, tolerances between these parts are liable to give rise to positioning errors, so that these tolerances necessitate further adjustments of the parts relative to each other. As a result of this, it is comparatively intricate to position the tape guides relative to the drum system in the known magnetic tape apparatus, so that even in the case of mass production the known apparatus is comparatively expensive.